1. Field of the Invention
The present invention relates to a drive apparatus and a semiconductor module.
2. Description of Related Art
A drive apparatus, which includes an electric motor to generate a torque, is known as a mechanism that assists a steering operation of a steering wheel of a vehicle. A brushless motor, which is rotated upon application of a three-phase alternating current, is often used as a drive power source of the drive apparatus. In the case where the brushless motor is used as the drive power source of the drive apparatus, it is necessary to generate alternating currents of different phases from a direct current output of a predetermined voltage (e.g., 12 V) to provide winding wire currents (i.e., electric currents) of different phases to winding wires of multiple phases (e.g., three phases), respectively. Therefore, in order to execute switching of the winding wire currents, an electronic circuit is required. In this instance, the electronic circuit includes semiconductor modules and a control circuit (e.g., a microcomputer). The semiconductor modules include semiconductor chips, respectively, which implement the switching function, and the control circuit controls operations of the semiconductor modules. For instance, Japanese Unexamined Patent Publication No. H10-234158A, Japanese Unexamined Patent Publication No. 10-322973A and Japanese Unexamined Patent Publication No. 2004-159454 (corresponding to US 2004/0090130A1) teach such a drive apparatus, in which the semiconductor modules are placed adjacent to the motor.
In the above drive apparatus, when the semiconductor modules are placed at predetermined locations, respectively, relative to a motor case, which receives the motor, the positions of the semiconductor modules may possibly be deviated at the time of manufacturing or after the manufacturing. Particularly, in a case where each of the semiconductor modules is placed upright (i.e., in its upright position) relative to the motor case, the semiconductor module may possibly be tilted or tumbled at the time of the manufacturing, thereby hindering a smooth workflow in subsequent manufacturing steps. In order to limit the positional deviation of the semiconductor module, a jig, which supports the semiconductor module, i.e., which positions the semiconductor module in place, may be used. However, in such a case manufacturing costs may possibly be disadvantageously increased.